Known is a gerotor type motor, comprising a hollow housing, a multiple-lead gear-rotored mechanism that is positioned in said housing and includes a coaxially disposed stator, and a rotor positioned within the stator, and also a spindle that is coupled, via a drive shaft, to the rotor and positioned within the spindle housing, the motor and spindle housings being interconnected using a bent substitute having threads on its edges [RU Patent 2149971, E 21B4/02, 7/08, 1999].
In this prior-art design the motor and spindle housings are connected to the bent substitute by means of threaded enclosures; the rotor and spindle being interconnected by the drive shaft using threaded adapters; the inner cavity of one of the threaded enclosures is provided with an annular bead, which bead accommodates a ring; the ring inner diameter is provided with a gap with respect to the drive shaft, and value of said gap does not exceed that of the substitute outer diameter; the bent substitute, on its edges, has threads having the crossing axes; and the longest distance between said threads axes is equal to the rotor s eccentricity with respect to the stator.
A disadvantage of this known design is as follows: setting of another angle value, and compensating of the lateral force imparted by the drilling bit using the reactive moment occurring on the substitute, the bent drilling string s motor and spindle, need disengagement of the motor from the spindle so that to enable replacement of the substitute.
Another disadvantage of this known design consists in an incomplete utilization of the possibilities for compensating the lateral force imparted by the drilling bit (at a certain value of angle on the substitute), and in a narrow range of said force, as the longest distance between the crossing threads axes does not exceed the value of the rotor eccentricity with respect to the stator.
This circumstance does not allow to compensate the positive and negatives peaks of fluctuations of the axial load on the drilling bit, and to maintain the optimum axial load on the drilling bit by preserving the axial load current values without loss of stability of a slanted-directional bent drilling string.
Known is the angle regulator, consisting of a central hollow element and three hollow mutually misaligned tubular elements connected with said central element, each of which three tubular elements has an inner through opening, wherein the inner hollow tubular element being disposed in the centre between the first and second elements, and the first and second tubular elements being connected to the inner hollow tubular element by the threads provided on their edges that face one another, the first and second tubular elements being connected by a thread to the gerotor type motor housing [U.S. Pat. No. 5,343,966, E 21B7/08, 1994].
In this known design, the first or second tubular elements are intended to connect the gerotor type motor housing to the spindle or a drill pipe, the central and inner hollow tubular elements being interconnected by a splined joint, and providing for re-setting of a new angle value when a drilling string is lifted, without disengagement from the downhole motor.
A disadvantage of this prior-art design is the lack of compensation of the lateral force imparted by the drilling bit by the use of the reactive moment occurring on the angle regulator, motor and spindle of a bent drilling string, during penetration through a well bottom heterogeneity.
In these circumstances, optimisation of penetration wells is difficult to achieve due to the difficulty to correct for the component of the lateral force exerted on the drilling bit, which force brings about the reactive bending moment that changes its direction (sign) when a slanted-directional bent drilling string loses its stability (see Gazovaya Promyshlennost Journal [Gas Industry], February 1998, pp. 42-44).
This difficulty affects accuracy of sinking the inclined wells due to the unforecastable component of the lateral force exerted on the drilling bit, so that drilling parameters cannot be optimized, and in particular the optimum axial load acting on the drilling bit cannot be maintained by preserving the axial load current values without loss of stability of the bent drilling string.
The art most pertinent to the claimed design is a regulator of an angle and reactive moment of a gerotor type motor, comprising:
a central hollow element and three hollow tubular elements connected to said central hollow element;
each of which the hollow tubular elements having a through opening;
a first tubular hollow element having one axis;
a second tubular hollow element having another axis;
an inner hollow element being disposed in the centre between the first and second elements, and having a third axis;
wherein the first and second tubular elements being connected to the inner hollow element by the threads provided on the edges facing one another;
the first hollow tubular element being connected to a spindle by a thread;
the second hollow tubular element being connected to the motor housing by a thread;
the central hollow element being connected to the inner hollow element by splines;
the inner hollow element having threads on its edges, the threads have axes that cross one another and the central axis;
the longest distance between said threads axes is the double value of the rotor eccentricity with respect to the gerotor type motor stator;
the longest distance between its central axis and axes of any of the threads on its edges being equal to the rotor eccentricity with respect to the gerotor type motor stator (U.S. Pat. No. 2,186,923, E 21B4/02, 7/08, 2000].
A disadvantage of this known design is an incomplete utilisation of a possibility to increase the deviation angle and improve penetrating capability of the gerotor type motor having a spindle and drilling bit in a bent drilling string by compensation of the resultant radially-unbalanced force generated during rotation of a drilling bit in a borehole.
In this prior-art design, the regulator has not its own contact segmental sections, which sections would improve stability of a bent drilling string, for example—any sections that would be provided at different sides with respect to the string bend plane and would ensure the continuous contact with the borehole wall in time of drilling, and also would further increase accuracy of penetration into a well bottom heterogeneity by way of providing an optimum axial load on the drilling bit, without loss of stability of the bent drilling string.